(19)

(11)

EP 2 748 951 A2

(12)

(88) Date of publication A3: 01.08.2013 (43) Date of publication: 02.07.2014 Bulletin 2014/27 (21) Application number: 12759808.4 (22) Date of filing: 24.08.2012

(51) International Patent Classification (IPC):  H04B 10/67(2013.01) G01H 9/00(2006.01) (86) International application number: PCT/GB2012/052095 (87) International publication number: WO 2013/027068 (28.02.2013 Gazette 2013/09)

(84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR (30) Priority: 25.08.2011 GB 201114717 (71) Applicant: OptaSense Holdings Limited Hampshire GU14 0LX (GB)	(72) Inventors: LEWIS, Andrew Bristol BS20 7FS (GB) RUSSELL, Stuart Bristol BS20 7FS (GB) (74) Representative: Day, Caroline Margaret  Haseltine Lake LLP 120 Redcliff Street Bristol BS1 6HU Bristol BS1 6HU (GB)